Security Advisory

Zend\Session\Validator\RemoteAddr and Zend\View\Helper\ServerUrl
were found to be improperly parsing HTTP headers for proxy information, which could
potentially allow an attacker to spoof a proxied IP or host name.

In Zend\Session\Validator\RemoteAddr, if the client is behind a proxy server,
the detection of the proxy URL was incorrect, and could lead to invalid
results on subsequent lookups.

In Zend\View\Helper\ServerUrl, if the server lives behind a proxy, the helper
would always generate a URL based on the proxy host, regardless of whether
or not this was desired; additionally, it did not take into account the proxy port
or protocol, if provided.

Action Taken

A new class, Zend\Http\PhpEnvironment\RemoteAddress, was
developed to provide reusable code surrounding the detection of a client IP via
proxy headers, and Zend\Session\Validator\RemoteAddr was refactored
to consume this class. This code:

no longer searches against the non-standard Client-Ip header

allows specifying the specific header to check against for proxy detection

allows specifying a list of trusted proxy servers against which to mask any detected proxy IPs

properly selects the right-most IP address from the list of proxy IPs

The ServerUrl view helper was modified as follows:

a flag was introduced to enable/disable proxy detection

proxy detection is disabled by default

in addition to using the X-Forwarded-Host

header, support for detecting
the proxy port (via the X-Forwarded-Port header) and proxy protocol (via the
X-Forwarded-Proto header) was added.

This patch has been applied starting in versions 2.0.5 of Zend Framework, as well
as to the 2.1 development branch.

Recommendations

If you are using any of the components listed, we recommend
upgrading to 2.0.5 or greater.

Other Information

Acknowledgments

The Zend Framework team thanks the following for identifying the issues and
working with us to help protect its users:

Fabien Potencier

Reporting Potential Security Issues

If you have encountered a potential security vulnerability in Zend
Framework, please report it to us at zf-security@zend.com. We will
work with you to verify the vulnerability and patch it.

When reporting issues, please provide the following information:

Component(s) affected

A description indicating how to reproduce the issue

A summary of the security vulnerability and impact

We request that you contact us via the email address above and give the
project contributors a chance to resolve the vulnerability and issue a new
release prior to any public exposure; this helps protect Zend Framework
users and provides them with a chance to upgrade and/or update in order to
protect their applications.

Policy

We will patch the current release branch, as well as the immediate prior
minor release branch.

After patching the release branches, we will immediately issue new
security fix releases for each patched release branch.

A security advisory will be released on the Zend Framework site
detailing the vulnerability, as well as recommendations for end-users to
protect themselves. Security advisories will be listed at http://framework.zend.com/security/advisories, as well as
via a feed (which is also present in the
website head for easy feed discovery)